the best spark plugs?...

[Lamotta81]

I want to double check, i am currently experiencing tach flutter low and high... Brand new engine but i didnt check the pluggs the mechanic installed.... are cr4ts's the correct pluggs any help is appreciated...

 

[jwaller]

for stock heads ya thats the right number.

the ngk's are also a good plug UR5 or UR6

 

[93ty475]

for stock heads ya thats the right number.

the ngk's are also a good plug UR5 or UR6

john,

what do you install on non stock heads? like heavily ported L35's? i didn't know that cr42ts, and ur5's were for stock heads only...

 

[jwaller]

I like the UR6's a bit better for trucks with port work and more boost bc they are a bit colder. if you begin to have plug issues with high boost and such ngk has some nitrous plugs that also work really well with tight gaps and no resistors.

 

[442typhoondude]

Try Denso's. They are made out of Iridium which is what the comet that took out the dinosaurs was made of. In a go cart motor my dad's buddy built, he switched to a cryogenically processed Denso and the horse power jumped from 10.2 to 10.4. Not much but if you consider how much extra HP that is on a go cart, it's quite noticeable. I can't back this up having not seen it with my own eyes but these plugs are what all of the high end race cars have been using lately. Very efficient powerful plugs. Not for a stock ignition though.
http://www.densoiridium.com/faq.php

 

[Sy769]

I am currently using the NGK UR6IX in my stock head Sy. I have used the UR5's and UR6's. I settled on the 6's because they seem to do a bit better at warding off detonation at high boost since they are a bit colder.

So far I can't say I can really tell a huge difference between the Iridiums and the std UR6. However they may last longer. I'll probably pull them at the Nats as I'll likely run race gas which is hard on plugs. The iridums aren't cheap.

 

[Wraith]

I am having the same issue with my ty, periodically i was getting some tach flutter. So I checked the plugs and there were cr43's in it and not the cr42's. I dont know the differences in these plugs, would this be causing the problem? Tommarrow I will be picking up a Conrad Brass Cap and Rotor set with Taylor SpiroPro wires and some UR5's. Just curious :roll:

 

[jwaller]

42 is what you need, and make sure they have the full part number

CR42TS.

not just the R42TS

 

[SpoolingTurbo6]

ds

ds

I use CR42TS's in the Sy but they don't last but a few months or so

Is this because of high F.P.? Or 60-1 turbo?

 

[Captain Morgan]

i love my NGK's.

I was never able to maintain 0* knock with the CR42TS's about a month after replacing them.

I went with the UR5's last June before I went to S-Series nationals and STILL have the same plugs in my truck this June with no idle or WOT problems.